Answers to your first exam

		GEOLOGY 106 - MIDTERM
		FALL 1999
		GEORGE STANLEY

I.	BRIEFLY DEFINE (30 Points)

1.	Half-Life -The time needed for half of the original quantity of radioactive atoms to decay 
	to daughter product.

2.	Charles Lyell -English geologist who published the Principles of Geology.  He established 
	cross-cutting and inclusions principles.

3.	Alluvial Fan - The abrupt deposition of stream-transported material where rivers emerge 
	from mountains.

4.	Craton - The long-stable region of a continent, commonly Precambrian crystalline rock.

5.	Eukaryote - Cell with true nucleus and nuclear membrane.  Reproduce sexually.

6.	Punctuated Equilibrium - Mode of evolution characterized by rapid change punctuated 
	by long periods of stasis.

7.	Mohorovici Discontinuity - Boundary separating Earth's crust from the underlying 
	mantle.

8.	Suspect terrane - A block or exotic real estate bound by faults and different from 
	adjacent blocks.  Syn. "Exotic terrane"

9.	Aulacogen - In plate tectonics, an inactive rift or  radiating 3-rift system.  Rifts widen to 
	become continental margins and one prong is the "failed arm." 

10.	Venodoza - Ediacaran creatures unlike metazoans today. Seilacher thinks they are 
	"aliens."

II.	 MULTIPLE CHOICE (20 Points, Circle One)

1.	The principle which stipulates that in any sequence of undisturbed strata, the oldest layer is 
	at the bottom and successively higher layers are successively younger is the:

a.	****Principle of Superposition ****
b.	Principle of Original Lateral Continuity
c.	Principle of Original Horizontality
d.	Principle of Stratigraphy

2.	The principle that states the past history of the earth can be interpreted in accordance with 
	our knowledge of natural processes still operating today is called:
 
a.	Biologic Continuity
b.	Law of Superposition
c.	****Law of Uniformitarianism**** 
d.	Law of Biologic Succession


3.	The geologic time scale was originally based on:

a.	****the succession of fossil assemblages**** 
b.	the theory of organic evolution
c.	the rock record
d.	the absolute age of rocks based on isotope age states

4.	What is the smallest particle size found in sedimentary rocks?

a.	silt
b.	****clay**** 
c.	fine sand
d.	granules

5.	Which of the following is not a primary sedimentary structure?

a.	mud cracks
b.	cross bedding
c.	****folds**** 
d.	ripple marks

6.	Which taxonomy list - from largest to smallest - is correct?

a.	order, species, family, genus, phylum kingdom, class
b.	species, genus, family, order, class, phylum, kingdom
c.	****kingdom, phylum, class, order, family, genus, species****
d.	species, order, genus, phylum, class, family kingdom

7.	Darwin's finches in the Galapagos Islands showed that species of related ancestry evolved 
	differently because they adapted to different environments.  This illustrates the concept of:

a.	convergent evolution
b.	parallel evolution
c.	phyletic gradualism
d.	****adaptive radiation****

8.	Seismic waves that are capable of travel through solid rocks, whose direction is parallel to 
	direction or propagation, and whose speed is the fastest of seismic waves are the:
 
a.	****primary waves ****
b.	secondary waves
c.	surface waves
d.	longitudinal waves


9.	Gondwanaland consisted of which three present day countries?

a.	Africa, Asia, Australia
b.	North America, India, Europe
c.	****India, Africa, South America or****
d.	****Australia, Africa, India****

10.	The process by which the early atmosphere of the Earth was derived from the Earth's 
	interior by vulcanism is called:

a.	sublimation
b.	photosynthesis
c.	****outgassing ****
d.	photochemical dissociation

11.	Relatively thin blankets of sedimentary strata that cover regions of stable, basement rocks 
	is called a:

a.	craton 
b.	****platform ****
c.	Precambrian Province
d.	shield

12.	The process whereby organisms release free oxygen (as a waste product) into the 
	atmosphere is called:

a.	respiration
b.	photochemical dissociation
c.	****photosynthesis****
d.	fermentation

13.	The oldest fossil evidence of stromatolite-like prokaryotes of the Warrawoona Group of 
	Australia occur in:

a.	****the 3.5 billion year old Pilbara shield****
b.	the 3.96 billion year old rocks in the Northwest Territories of Canada
c.	the 3.8 billion year old banded iron formations of southern Greenland
d.	the 3.1 billion year old Fig Tree Group of South America

14.	The eon that began 2.5 billion years ago and ended 544 million years ago and contains 
	42% of the Earth's history is the:

a.	Neoproterozic
b.	Archean
c.	****Proterozoic****
d.	Hadean

15.	A large-scale, lithostratigraphic unit that represents a major transgressive-regressive cycle 
	and is bounded by a regional unconformity is called a:

a. 	platform
b.	shield
c.	****sequence****
d.	cyclotherm

16.	An extensive accumulation of mostly clastic sediments that are deposited in an area 
	adjacent to an unlifted region is called a(n):

a.	depositional basin
b.	****clastic wedge or****
c.	structural dome
d.	****alluvial fan****

17.	The most abundant of the Early Paleozoic arthropods is the:
a.	brachiopod
b.	graptolite
c.	insect
d.	****trilobite**** 

18.	Ash beds, associated with the great volcanism that occurred during the rising of the 
	taconic ranges have been weathered to a clay called:

a.	****bentonite**** 
b.	siliceous shales
c.	graptolites
d.	zircon

19.	The Cambrian animal, Pikaia, of the Burgess Shale is important because it:

a.	represents the first animals to develop appendages
b.	****was the first known member of the phylum Chordata**** 
c.	shared characteristics with Cnidaria
d.	defies any similarity to any forms known on Earth today

20.	At the end of the Permian Period nearly half of the known families of animals disappeared 
	because of:

a.	consolidation of the Pangean supercontinent
b.	high elevations of many regions on Pangea
c.	development of polar ice caps
d.	****all of the above**** 

III.	FILL IN THE BLANK (20 Points)

1.	The oldest rocks of our planet that make up the Archean and Proterozoic are collectively 
	referred to as the              Precambrian                                                    .

2.	Populations whose members can interbreed when they come into contact are grouped into 
	that larger biologic unit called a           species                                                               .

3.	The evolutionary pattern that occurs when two or more unrelated lineages acquire similar 
	morphologic traits, usually because of adaptations to similar modes of life and 
	environment, is called             convergent evolution or convergence                                

4.	In Alfred Wegener's theory of continental drift, the super-continent included in all of 
	present day major continental masses is called                Pangea                                   .

5.	Because pelycosaurs had skeletal characteristics similar to mammals they are thought to 
	have given rise to the more advanced mammal-like reptiles called     synapsids                 

IV.	TRUE - FALSE (12 Points)

1.	           T         	The "Principle of Faunal Succession" is dependent on organic evolution.

2.	           F        	The approximate age of the oldest sediments on the sea floor are 
				approximately 500 million years old.

3.	           F        	Prokaryotes were organisms with a definite nuclear wall, well defined 
				chromosomes, and the capacity for sexual reproduction.

4.	           T       	The development of the Catskill Clastic Wedge was a result of erosion of 
				highlands formed during the Acadian Orogeny.

5.	           T       	The amniotic egg is one of the most significant evolutionary changes that 
				enabled amphibians to live on land.

6.	           F       	The extinctions that characterize the Late Paleozoic occurred primarily 
				among terrestrial vertebrates (reptiles and amphibians) while only a few 
				marine invertebrates were affected.
 
SHORT ESSAY (18 Points, Pick Two)

1.	How does natural selection differ from Lamarckism?  Use an example to illustrate (note: 
	giraffes are not allowed).

 Lamarckism involves a mysterious "urge" of an organism to change toward a direction of 
progress.  Increasingly better traits are transmitted directly to offspring by the "inheritance 
of acquired characteristics."  Natural selection in contrast, admits great variation and 
preferential reproductive success among populations.  It relates to selection by nature, or 
of characteristics selected by a given situation or environment.  Cut off the tails of enough 
rat populations, and you will get a tailless rat says Lamarck.  Darwin says, rat tails in a 
population of rats all vary in length and if the environment imposes a special situation 
where short or tailless rats have a selective edge or advantage, that part of the population 
will increase in numbers at the expense of the longer tails.  The result will be shortened or 
eventually tailless rats given enough time.  In this scenario, there is no progress or 
direction toward any goal.  In the change, the populations just shift through time.  Review 
the differences carefully.

2.	In the plate tectonic model, what are the two regions of plate interaction?  What three 
	lines of evidence helped confirm plate tectonics and continental drift?  Discuss.

The two regions of plate interactions are: 1) the subduction zone and 2) the spreading 
center, often a mid-ocean ridge.  In the first, crust is lost while in the second new crust is 
created.  The evidence could be: 1) magnetic stripes on the sea floor, 2) the match up of 
fossils, 3) ages of the sea floor, growing progressively younger toward the spreading 
center, etc.

3.	Define progress and determinism.  What does the Burgess Shale tell us about these biases? 
	Sketch the cone of increasing diversity.  What is the alternative model?

Progress - life is moving toward some clearly defined goal with clear directions.  Simple to 
advanced.

Determinism - The history of life is predetermined.  Life has evolved following some 
determined events.  If the "tape of life" could be rewound, it would play the same way 
each time.  The Burgess fossils speak against these by showing that the most advanced 
forms evolved first--Pikaia for example.

The testing of new, often bizarre, body plans and that the body plans selected had no clear 
direction, meaning that it was pretty much random in the statistical sense.  Sketch the cone 
of increasing diversity (Darwin's idea) vs. the decimation model (the alternative idea).